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Parallelweg 9 2921 LE • PO box 701 2920 CA • Krimpen aan den IJssel The Netherlands P +31 (0)180 514 055 • F +31 (0)180 517 264 • E [email protected] • www.tiobv.nl TIO BV The leading silencer company since 1934 Expansion joint °C thermal expansion thermal expansion factor carbon steel factor stainless steel avg. 12,0 17,0 20 10,9 16,4 100 11,5 16,8 200 12,3 17,3 300 12,9 17,6 400 13,6 17,9 500 14,2 18,4 600 14,6 18,7 Expansion joints are an important part in each exhaust pipe. The convoluted section of the expansion joint is designed to accommodate the movements due to thermal expansion in the piping system. It also prevents the propagation of vibra- tions. Consequently the expansion joints have to be as flexible as possible. This flexibility is acquired by the use of very thin material as well as by making the bellows as high as possible. All the expansion joints which TIO has in her delivery pro- gram are therefore built out of several courses of stainless steel, through which a large accommodation of the move- ments is possible at a minimum axial and lateral load. The multiply, stainless steel bellows are hydraulic forced. This production method guarantees high flexibility and a durable performance. With or without inner tube? TIO multiply, stainless steel expansion joints can be executed with or without an inner tube. De advantages of an expansion joint with an inner tube are a durable performance and less back pressure. The disadvantage on the contrary is the limi- tation of the lateral movement. Although TIO has both executions in her delivery program, the disadvantage of the limitation of the lateral movement is such, that it is better to choose for an expansion joint without an inner tube. The back pressure is negligible and due to the multiple construction the service life is nearly the same. How many expansion joints must be applicated and where do they have to be installed? The answer to this question depends on the length and the course of the exhaust pipe. The sum of the axial expansion can be calculated with the assistance of the next formula: ∆L = L 0 x α x ∆t If you multiply the length of the exhaust pipe (L 0 ) by the lineair expansion coefficient α between T min and T max (∆T), you will get the sum of the axial expansion (∆L). Like any other material, steel will expand too when it is heated. The undermentioned table contains several thermal expansion factors of carbon and stainless steel at different temperatures: Thermal expansion factor α, 1°C (multiply tabulated values bij 10 -6 ) Example • length exhaust pipe = 4.500 mm • material exhaust pipe = carbon steel • temperature min. = 20°C • temperature max. = 450°C • α average (ST37.2) = 12 x 10 -6 ∆L = 4.500 x 12 x 10 -6 x 430 = 23,22 mm
